Stability of interlinked neutron vortex and proton flux tube arrays in a neutron star. II. Far-from-equilibrium dynamics

摘要

The equilibrium configurations of neutron superfluid vortices interactingwith proton superconductor flux tubes in a rotating, harmonic trap arenon-trivial in general, when the magnetorotational symmetry is broken. Anon-zero angle $\theta$ between the magnetic and rotation axes leads to tangledvorticity due to competition between vortex-vortex repulsion andvortex-flux-tube pinning. Here we investigate the far-from-equilibriumbehaviour of the vortices, as the trap decelerates, by solving thetime-dependent, stochastic, Gross-Pitaevskii equation numerically in threedimensions. The numerical simulations reveal new vortex behaviours. Keygeometrical attributes of the evolving vortex tangle are characterised, as isthe degree to which pinning impedes the deceleration of the neutron condensateas a function of $\eta$, the pinning strength, and $\theta$. The simulatedsystem is a partial analogue of the outer core of a decelerating neutron star,albeit in a very different parameter regime.